1- Biological Molecules

Question 1

monomer=

Answer 1

smaller units from which larger molecules (polymers) are made

Question 2

polymers are held together by=

Answer 2

covalent bonds

Question 3

monomer e.g.s

Answer 3

amino acids, nucleotides, monosaccharides

Question 4

condensation reactions=

Answer 4

joining of 2 molecules by forming a chemical bond and eliminating 1 x H20

Question 5

hydrolysis reaction=

Answer 5

breaking of a chemical bond between 2 molecules & involves addition of 1xH20

Question 6

monosaccharide

Answer 6

monomers from which larger carbohydrates are made

Question 7

monosaccharides e.g.s

Answer 7

glucose, galactose, fructose

Question 8

Polysaccharides are held together by:

Answer 8

glycosidic bonds

Question 9

disaccharides=

Answer 9

• maltose (glucose+glucose)
• sucrose (glucose+fructose)
• lactose (glucose + galactose)

Question 10

what are the 2 isomers of glucose?

Answer 10

• a-glucose

- B-glucose

Question 11

what is an isomer?

Answer 11

two or more compounds with the same molecular formula, but different arrangement of atoms

Question 12

a vs b arrangement

Answer 12

a b

H O H H O H

HO OH HO H

Question 13

which polysaccharide(s) are formed from a condensation of a-glucose?

Answer 13

glycogen & starch

Question 14

which polysaccharide(s) are formed from a condensation reaction of B-glucose?

Answer 14

cellulose

Question 15

polysaccharide features (2)

Answer 15

• can be branched or unbranched

- chain may contain different types of monosaccharides

Question 16

Starch- functions (2)

Answer 16

• main energy storage in plants (in seeds)
• can act as food source for humans
• broken down into glucose by plants when they need energy

Question 17

Starch- features (1)

Answer 17

• does not change water potential in a cell because its insoluble in water

Question 18

2 types of starch =

Answer 18

1. amylose

2. amylopectin

Question 19

amylose vs amylopectin

Answer 19

amylose= unbranched, good for energy storage
amylopectin= branched, good for energy release

Question 20

glycogen structure (2)

Answer 20

• compact (so good storage molecule)

- highly branched (so can be easily converted to glucose)

Question 21

cellulose structure=

Answer 21

• long chain of B-glucose

- B-glucose molecules linked by glycosidic bonds to form LINEAR cellulose chains that are unbranched

Question 22

what are myofibrils

Answer 22

strong fibres made up of many cellulose chains that are held together by H bonds

Question 23

how does cellulose provide structural support to plants

Answer 23

because of the strength of myofibril fibres they are composed of

Question 24

digestion of cellulose=

Answer 24

• broken down by human digestive enzymes

- herbivores can digest cellulose rich plant material

Question 25

Benedicts test for R sugars

Answer 25

1. place 2ml of substance in boiling tube
2. add 10 drops of Benedict’s solution
3. Place in boiling water for 3-5 minutes
4. If G/Y= some RS, If O/R= moderate RS, if Brick red= large amounts of RS

Question 26

Benedicts test for NR sugars=

Answer 26

1. Do benedict’s (will be - result)
2. Boil in dilute HCL (to hydrolyse NRs)
3. Neutralise solution by adding sodium hydrogen carbonate
4. Repeat Benedict’s (will be + result)

Question 27

Triglyceride structure=

Answer 27

1x glycerol
3x fatty acid
held together by ester bonds

Question 27

Triglyceride structure=

Answer 27

1x glycerol
3x fatty acid
held together by ester bonds

Question 27

Triglyceride structure=

Answer 27

1x glycerol
3x fatty acid
held together by ester bonds

Question 28

Phospholipid structure=

Answer 28

1x glycerol backbone
2x fatty acid
1x phosphate group

Question 29

amino acid structure=

Answer 29

NH2= (an amino group)
COOH= (a carboxyl group)
H= (H atom)
R= (side group)

Question 30

which structure of proteins have ionic bonding

Answer 30

tertiary structure

Question 31

What are dispulphide bridges=

Answer 31

covalent bonds within proteins containing C amino acids

Question 32

Protein- primary structure=

Answer 32

order of amino acids in polypeptide

Question 33

protein- secondary structure=

Answer 33

• Primary polypeptide FOLDS and aa form H bonds with other AA
• This causes the protein to fold or coil
• mainly alpha-helix or beta pleated sheet arrangement

Question 34

protein-tertiary structure=

Answer 34

• Secondary polypeptide FOLDS further to form a tertiary structure
• interations between R groups create the tertiary structure
• this is usually coiled or folded
• Holding tertiary structure can be ionic bonds, H bonds and disulphide bridges

Question 35

Protein- Quaternary structure=

Answer 35

when multiple 3D polypeptides (subunits) can come together to form a complex, quaternary structure

Question 36

Main protein function e.g.s (3)

Answer 36

• structural proteins
• enzymes
• antibodies

Question 37

Biuret test=

Answer 37

1. Add sample to distilled water & biuret solution
2. Shake solution & leave upright for 5 mins
3. Observe colour: if PURPLE- protein is present

Question 38

Will the biuret test give a + result if free floating AA are in it?

Answer 38

No, they must be joined by peptide bonds to give + result

Question 39

Induced fit model=

Answer 39

As enzyme & substrate come together, this interaction causes a small shift in enzymes structure < this shift means enzyme & substrate can bind to form an E-S complex & catalyse a reaction

Question 40

specificity of enzymes determined by= (2)

Answer 40

• active site

- environmental factors (temp, pH)

Question 41

Factors affecting rate of enzyme action (5)

Answer 41

• temp
• pH
• competitive & non-competitive inhibitors
• enzyme conc
• substrate conc

Question 42

Formula for calculating H+ conc=

Answer 42

pH= log10 [H+]